Rotary inflow compressors and the like



Dec. 8, 1970' R. c, WEATHERSTON ET L 5 ROTARY INFLOW COMPRESSORS AND THE LIKE Filed Sept. 18, 1968 I0 26 28 3O I 58 ir i .5 I FlG.l

- INVENI 'ORS ROGER C THfRSTO/V GEORGE U1? YEA United States Patent US. Cl. 417-440 9 Claims ABSTRACT OF THE DISCLOSURE A rotary inflow compressor and/or expander having one or more piston members rotating in an annular chamber, the inner wall of which comprises a rotary sleeve valve adjacent the piston and cooperating with one or more abutment members rotating in timed relation with the piston members.

BACKGROUND OF THE INVENTION The present invention relates to improvements in rotary fluid compressors and expanders, and more particularly, to rotary compressors and expanders incorporating rotary abutment members wherein the working fluid is conveyed through the rotational axis of the working members.

Rotary abutment compressors are known wherein the working fluid is exhausted through the rotational axis of the working members. Examples of such compressors are disclosed in Pat. Nos. 2,559,590 and 2,690,869. In compressors of this type, the inner wall of the annular compression chamber is fixed and the bottom end of a piston working member rotates between this inner wall and a fixed outer wall of the compression chamber. There is also relative motion between one side face of the piston and a fixed cover plate member. There is thus exposed full-time leakage paths on the bottom and one side of the piston. The increased leakage paths reduce the efliciency of the compressor.

In addition, inthe foregoing types of compressors the piston member is supported on only one side face thereof, permitting the unsupported side face to deflect.

Moreover, in the form of prior type devices that incorporate a sleeve valve for communicating the compression chamber with the axial discharge passage, the rotary part of the sleeve valve is interior to the fixed part thereof. There are thus, four adjacent surfaces that are in relative motion, making it more diflicult to hold a close alignment between these relatively moving surfaces.

SUMMARY OF THE PRESENT INVENTION The foregoing, and other, disadvantages of the prior type of rotary abutment compressors are overcome according to the principles of the present invention.

According to the present invention the annular compression chamber comprises a cylindrical bottom wall that rotates with the piston working member about a stationary axial discharge flow passage. There is, thus, no full-time bottom leakage path leading from the bottom of the compression chamber. Additionally, the side walls of the compression chamber may rotate with the bottom wall and the piston such that the full-time side leakage path is eliminated. The rotary side wall may also serve to support the piston on both side faces thereof for better structural support.

In addition, the sleeve valve of the mechanism of the present invention has a rotary part that is external to the stationary part thereof and is incorporated into the same moving part that forms the cylindrical bottom wall of the compression chamber. In this manner, it is necessary to maintain close tolerances between only three members Patented Dec. 8, 1970 that are in relative angular motion and adjacent each other.

Other advantages and objectives of the present invention will become apparent as the description thereof proceeds.

BRIEF DESCRIPTION OF THE DRAWINGS For a more fuller understanding of the present invention, reference should be had to the following detailed description of the same taken in conjunction with the accompanying drawings wherein;

FIG. 1 is a longitudinal sectional view along the line 1-1 of the compressor showing the same in a multistaged arrangement, and

FIG. 2 is a sectional view taken along line 2-2 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, the numeral 10 depicts generally the improved mechanism of the present invention employed as a multistaged compressor. Of course, it is to be understood a simple reversal of the compressor action will permit the apparatus to function as an expander. A casing 12 with end cover plates 14 and 16 support and enclose the working parts. Top plate 18 may be provided for ease in assembly of the internal parts. An abutment support shaft 20 is rotatably supported and sealed in the casing by suitable conventional end bearing and seal assemblies 22 and 24. Abutment members 24, 26, 28, and 30 are fixedly mounted to shaft 20 at spaced intervals therealong by means of pins 32, 34, 36, and 38 or the like. As shown, each abutment is generally cylindrical and continuous except for a contoured cutaway escapement section 40. The escapments 40 are spaced about from each other on each abutment. A plurality of holloW bores 42 are provided substantially diametrically opposed to each escapement 40 to counterbalance each of the abutment members, due to the mass of material thereof removed to provide the escapement contour.

A stator shaft 44 is suitably fixedly mounted to the casing about an axis that is parallel to the axis of abutment shaft 20. The stator 44 has a hollow interior providing an outlet fiow passage 46. Rotatably mounted about the exterior of shaft 44 is a piston supporting annular rotor 47, and is supported by suitable bearings 48 and 49 between the rotor ends and the stator stator shaft 44-. Rotor 47 includes as a part thereof a plurality (four of which are shown) of generally U-shaped channels each defined by a inner cylindrical surface 50 and opposed radially projecting side walls 52. A removable piston member 54 is fixedly attached to the side walls 52 in each U-shaped channel as by pins 56. Material may be removed from rotor 47 as at 57 to counterbalance the same. In the case of four channels as shown, each piston member (only two of which are shown) is spaced about 90 from its adjacent piston member. The piston members are so contoured as to smoothly cooperate with the contoured cutaways 40, as shown. A stationary hollow cylinder 5 8 is fixed to the casing and surrounds the peripheral surface of side walls 52 to provide a closure for the U-shaped channels. Suitable recesses 60 are provided in cylinder 58 to allow the several abutment members 24, 26, 28, and 30 to pass into their respective U-shaped channels between the side walls 52 thereof. As shown in FIG. 2, the arcuate extent of each of the recesses 60 is sufficient to allow flow from inlet port 62 to the U-shaped channels.

Referring again to the hollow stator shaft 44, it is to be noted that the passage 46 communicates with an outlet 64 leading to a suitable point of use. A plurality of radial channels 66, 68, 70, and 72 are provided extending from the outer peripheral surface of shaft 44 to the interior passage 46 thereof. A plurality of ports 74 are located in the inner surface 50 of rotor 47 to provide communication, at the appropriate time, between the U-shaped channel and passage 46 via radial channels 66, 68, 70, and 72.

In the operation of the apparatus, as thus far described, shaft 20 is driven by a suitable source (not illustrated) to rotate the abutment members 24, 26, 28, and 30 counterclockwise as viewed in FIG. 2. Suitable timing gears 75 may be provided to establish a synchronized rotation of rotor 47, piston 54 and the U-shaped channels defined by inner surface 50 and side walls 52.

Air or other suitable fluid to be compressed enters the U-shaped channels substantially unrestricted via passage 62 and the recesses 60 in which it undergoes compression by the action of pistons 52 and the abutment members 30'. As the pistons approach the end of their compression stroke (the position shown in FIG. 2) the slots or ports 74 immediately upstream thereof open communication between the compressed fluid and the outlet passage 46 via channels 72. In this manner, inner surface 50 with its ports 74 function as a sleeve valve allowing the high pressure fluid to escape to the outlet in a smooth and eflicient manner. The ports 74 each have a sufiiciently small circumferential dimension such that there is virtually no leakage loss from the high pressure area to the inlet through the peripheral surface of the abutment and the rotor via the ports as they rotate beyond channel 72. In the case of lower pressure operation where member 47 may be very thin, it is possible to have only a single port.

An additional feature of the multipiston apparatus is that of capacity turndown. This is accomplished by the action of a piston 76 slidable in passage 46. The piston is guided by a stem 78 passing through a bore 80 in the stator housing 44. A series of by-pass plug valves 82 or the like are provided to control flow from the high pressure region in the U-shaped channel via passage 84 to the low pressure inlet via passage 86. The piston can be moved to positions whereat any one of the outlet channels is shut off from communication with the remaining channels. For example, in the dashed line position shown in FIG. 1, the channel 72 remote from outlet 64 is shut oif from the other channels. In which case, the valve 82 associated with this channel would be opened to relieve the pressure build-up in this isolated compression chamber by allowing fluid to by-pass back to the inlet. This allows the piston to free wheel in its chamber. Here the output of the compressor would be reduced by 25 percent. If the piston 76 is pushed into the passage 46 to isolate two or three pistons, the output could be reduced by 50 percent or 75 percent, respectively.

If such a capacity turndown feature is not desired, it would be possible to eliminate the piston 76 and the valves 82 and allow an additional outlet passage through bore 80.

From the foregoing, it should be readily apparent that since there is no relative motion between the bottom and sides of the pistons and the compression chamber, these potential leakage paths are eliminated.

In addition, since the rotary sleeve valve 74 is incorporated into the same rotor and is external of the stator, it is only necessary to hold close alignment between only three adjacent members that are in relative angular motion.

Although the foregoing description has assumed compressor operation, it is obvious that the present apparatus could function equally as well as a fluid motor or expander. In which case, passage 46 would be a high pressure fluid inlet and 62 would be the outlet.

A preferred embodiment has been disclosed and described. Modifications will occur to those skilled in the art without departing from the spirit of the present invention; which, accordingly, should be limited only by the scope of the appended claims.

We claim:

1. Apparatus of the character described, comprising;

(a) a stator shaft having an interior passage extending therethrough,

(b) a cylindrical sleeve rotor mounted exteriorly of said stator for rotation thereabout,

(c) a piston fixedly attached to said rotor for rotation therewith,

(d) port means through said rotor for placing the interior passage of said stator in communication with the exterior thereof in certain rotational positions of said rotor,

(e) said port means located adjacent said piston, and

(f) said port means through said rotor comprise circumferential spaced openings adjacent said piston each having a small circumferential dimension whereby there is virtually no leakage loss from the high pressure area to the inlet through the periphery surface of the abutment and the rotor via the openings as they rotate beyond said passage.

2. Apparatus according to claim 1, further comprising;

(e) a stationary generally cylindrical member surrounding said piston and providing with said cylindrical sleeve rotor an annular chamber, and

(f) a recess in said cylindrical member,

(g) a rotary abutment member mounted for rotation in timed relation with said rotor and passing through said recess, and

(h) a cutaway in said abutment member adapted to receive said piston.

3. Apparatus of the character described, comprising;

(a) a stator shaft having an interior passage extending therethrough,

(b) a cylindrical sleeve rotor mounted exteriorly of said stator for rotation thereabout,

(c) a piston fixedly attached to said rotor for rotation therewith,

(d) port means through said rotor for placing the interior passage of said stator in communication with the exterior thereof in certain rotational positions of said rotor,

(e) a stationary generally cylindrical member surrounding said piston and providing with said cylindrical sleeve rotor an annular chamber,

(f) a recess in said cylindrical member,

(g) a rotary abutment member mounted for rotation in timed relation with said rotor and passing through said recess,

(h) a cutaway in said abutment member adapted to receive said piston, and

(i) said port means through said rotor comprise circumferential spaced openings adjacent said piston each having a small circumferential dimension such that there is virtually no leakage loss through the peripheral surface of said abutment and said rotor via said ports.

4. Apparatus according to claim 3, further comprising;

(j) additional pistons fixedly attached to longitudinally spaced points on said rotor,

(k) said generally cylindrical member surrounding said additional pistons and providing with said cylindrical sleeve rotor additional annular chambers,

(1) additional longitudinally spaced rotary abutment members mounted for rotation in timed relation with said rotor,

(in) additional cutaways in each of said additional abutment members, and

(n) additional port means through said rotor adjacent to said additional pistons.

5. Apparatus according to claim 4, further comprising;

(0) valve means in said stator shaft intereior passage operable to block communication between one or more portions of said interior passage that communicates with one or more of said port means and the remaining portions of said interior passage.

6. Apparatus according to claim 5, further comprising;

(p) passage means in communication with said annular chambers, and

(q) feedback valve means operable to permit by-pass communication between each of said annular chambers and said passage means.

7. Apparatus according to claim 6, wherein;

(r) said valve means in said interior passage comprises a piston valve member.

8. Apparatus according to claim 7, wherein;

(5) said port means through said rotor comprise spaced openings adjacent said additional pistons each having a small circumferential dimension such that there is virtually no leakage loss through the peripheral surface of said abutment and said rotor via said ports.

9. Apparatus according to claim 3 wherein;

(j) said annular chamber has a pair of circumferential side walls projecting from and fixed to said rotor, and

(k) said piston is fixed to each side Wall.

References Cited UNITED STATES PATENTS 5/ 1912 Weddington 103-125 8/1916 McCarthy 123-13 8/1921 Smith 91-92 3/1930? Rosett 2-30-150 2/1937 Sunderland 123-13 9/1938 Whitfield 230-150 6/1966 Karlby et a1 103-125 FOREIGN PATENTS 5/1964 Great Britian 230-150 15 HENRY F. RADUAZO, Primary Examiner US. Cl. X.R. 

